The present invention relates generally to digital multimeters. More particularly, the invention relates to a digital multimeter having an improved shield arrangement for the internal printed circuit board.
Digital multimeters (DMMs) function to measure a number of electrical parameters as needed for service, troubleshooting and maintenance. Such parameters may include AC voltage and current, DC voltage and current, resistance and continuity. In some cases, a DMM may measure other parameters such as capacitance and temperature.
A DMM will often be configured as a hand-held unit having a rotary knob by which various functions are selected. A plurality of lead jacks are provided in the case (i.e., housing) of the unit for connection of test leads. The specific jack used may depend on the function that has been selected. An LCD display provides a reading of the tested parameter.
Various electronic components necessary for operation of the multimeter are typically mounted to a circuit board located inside the case. A top shield and a separate bottom shield cover portions of the top side and bottom side of the circuit board, respectively. The shields reduce the effects of interference on the operation of the multimeter.
Details regarding the construction and operation of multimeters may be discerned from U.S. Pat. Nos. 7,034,517, 6,466,003 and 6,043,640, incorporated herein by reference.